From wall graft to roof graft: reassessment of femoral posterior cruciate ligament positioning.
Academic Article
Overview
abstract
In many technique guides for posterior cruciate ligament (PCL) reconstruction, the PCL is depicted on the wall of the medial femoral condyle (MFC). We hypothesized that most of the anterolateral (AL) bundle originates on the roof of the intercondylar notch (ICN), not on the wall. Using a surgical navigation system, we delineated and morphed in the computer the entire PCL footprint-the AL bundle, the posteromedial (PM) bundle, and the Humphrey ligament (HL)-of 7 fresh-frozen cadaveric specimens. A clock face was defined in the en face view, with the 12-o'clock axis pointing anteriorly through the top of the notch and the roof being the region between 10 o'clock and 2 o'clock. The AL-bundle, PM-bundle, and HL positions were calculated in terms of this clock-face definition. Mean centroids (o'clock position) over all specimens of AL bundle, PM bundle, and HL were, respectively, 10:49, 9:43, and 9:00 on the left knee and 1:11, 2:17, and 3:00 on the right knee. Mean areas were 63 mm(2) (AL bundle), 63 mm(2) (PM bundle), and 45 mm(2) (HL). In 5 of the 7 specimens tested, 100% of the AL bundle originated on the roof of the ICN. Conversely, 66% of the PM bundle and 100% of the HL inserted on the wall of the MFC rather than on the intercondylar roof. Using computer navigation software, we determined that most of the AL bundle originates on the roof of the ICN and that the PM bundle is centered near the transition between the roof and the wall of the MFC. These findings contradict the depiction in most technique guides for PCL reconstruction. Implant companies and surgeons should modify their techniques to shift PCL graft tunnels from the wall of the MFC to the roof of the ICN.
